Ground bushing

ABSTRACT

THIS IS A GROUND BUSHING ADAPTED TO ENGAGE A SOFT METAL GROUNDING PLATE WHICH WILL BE FLUSH WITH THE UPPER SURFACE OF THE GROUNDING PLATE AFTER ENGAGEMENT.

United States Patent inventor William H. McKee West Covina, Calif. Appl. No. 802,012 Filed Feb. 25, I969 Patented June 28, 1971 Assignee United-Carr Incorporated Boston, Mass.

GROUND BUSHING 2 Claims, 6 Drawing Figs.

US. Cl. 339/14, 339/95, 339/256 Int. Cl. H01!- 3/06 Field ofSearch 339/14, 95, 2 2 l 2 5 6, 2 5 8 [56] References Cited UNITED STATES PATENTS 2,788,506 4/1957 Young 339/256 2,970,287 1/1961 Gill 339/l4(L) 3,122,604 2/1964 Cook et al. 339/95(D)X 3,333,234 7/l967 Kindersley et al. 339/22 lX 3,480,904 I 1/1969 Gluntz 339/14(R)X Primary Examiner-Marvin A. Champion Assistant ExaminerRobert A. l-lafer Altorneys Philip E. Parker, Gordon Needleman, James R.

O'Connor, John Todd and Hall and l-loughton ABSTRACT: This is a ground bushing adapted to engage a soft metal grounding plate which will be flush with the upper surface of the grounding plate after engagement.

Patented June 28, 1971 2 Sheets-Sheet 1 F|G.l

INVENTOR WILLIAM H. MC KEE 5% ATTORNEYS Patented June 28, 1971 3,588,182

2 Sheets-Sheet 2 INVENTOR. WILLIAM H. McKEE ATTORNEY Y GROUND BUSHING BACKGROUND OF THE INVENTION Frequently it. is desirable to connect from a terminal or contact tail to a voltage or ground plate. Some of the early methods of electrically engaging a contact or terminal or a series of contacts or terminals to a common voltage or ground plate was to solder, braze or weld directly from the terminal to the plate. These methods had limitations because all materials could not be joined in these manners nor could some materials withstand the heat required to make this type of joint.

Another method was to utilize a metal bushing as an intermediate connection being crimped to the terminal and then press-fitted into an aperture in the plate. In this case there was merely a friction fit between the bushing and the plate which has certain disadvantages. For example, the assembly may be subjected to heat causing thermal expansion, which may vary between the plate and bushing having, in turn, deleterious effects upon the integrity of the electrical connection between the bushing and plate. In addition, the plate may be a soft metal and any mechanical action between thQ'SOft metal bushing and soft metal plate could cause a poor electrical connection between the bushing and plate. If it is necessary to remove a terminal in either of the two mentioned methods considerable effort is required and the possibility of damage to the assembly is great. 7

Another method is the use of a hard bushing containing spring fingers to grip the terminal and a knurled outside diameter to be driven into the plate. While this method allows for easy replacement of the terminals, it, like the other methods, cannot be practically made small enough to not extend above either surface of the plate. Plates in common use are often as thin as 0.050 inches.

SUMMARY OF THE INVENTION This invention is directed at a ground bushing that will make an electrical connection between a terminal and an aluminum or soft metal plate.

An object of the present invention is to provide a contact which will make a gas tight connection with an apertured plate. Another'object of the present invention is to provide a bushing which will have flexible means adapted to closely engage the terminal of contact tail.

Another object of the invention is to provide a bushing which when engaged in the plate will be flush or below flush on both sides of the plate.

Still another object of the invention is to provide a bushing that will allow for easy terminal replacement. A final object is to provide a bushing more economical to make and use than those commonly used.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective of the ground bushing, terminal and plate;

FIG. 2 is a top plan view of the ground bushing;

FIG. 3 is a side elevation of the ground bushing;

FIG. 4 is a bottom plan view of the ground bushing;

FIG. 5 is a perspective of the ground bushing; and

FIG. 6 is a side elevation of the plate, terminal and ground bushing showing the ground bushing just before it is driven into the plate.

DESCRIPTION OF THE PREFERRED EMBODIMENT The ground bushing 9 comprises a pair of straps 10 in spaced parallel relation to each other and connecting together two engagement portions 12. The engagement portions 12 are also in spaced parallel relation to each other and with the straps 10 define a rectangular opening 14. Each of the engagement portions 12 is on a side edge and is generally rectangular in configuration and being arced to provide extensions 16 at each corner of the rectangle. Each of the extensions 16 provide a cutting or engagement edge 18. The straps 10 that are positioned below the engagement portions 12 provide a leadin, along with the curved portions of the extensions 16, into an aperture 20 formed in an aluminum or soft metal plate 22. To

engage the bushing with the pin portion 24 of a connector contact and the plate 22, the bushing is dropped over the pin 24 with the straps 10 down as shown in FIG. 6. The contact will drop freely until the straps 10 are in the aperture 20 of the four extensions 16 are resting adjacent the aperture 20. The bushing is driven into the grounding plate 22 with a flat ended rod having an axial relief hole through which the pin 24 extends. The bushing is driven flush with or slightly below the surface as shown in FIG. 1. The four engagement edges 18 are driven into the material of the grounding plate 22 providing a good electrical connection. As the contact is driven into the plate 22 the engagement portions 12 are bowed toward each other to firmly press against the sides of the pin portion 24. The particular embodiment shown by the inventor has a smooth engagement edge 18 but if desired, a series of saw teeth may be formed.

It can easily be seen that the grounding contact could be driven in the opposite direction if the rounded edge lead-ins on elements 16 were moved from the lower corners to the upper comers.

It can also easily be seen that the grounding contact would function if the straps 10 were omitted and the two engagement halves 12 were separately placed in the aperture and then driven as described for the complete part.

I claim:

1. A ground bushing having a pair of opposed engagement portions having inner faces in spaced facing relation each of said engagement portions having upper and lower edges and end edges, a pair of straps each of which is joined to said inner faces of said engagement portions so as to connect said engagement portions, said straps being in spaced relation and combining with portions of said engagement portions between said straps to form a rectangular opening, said straps being yieldable to engage under tension a contact post inserted between them, said straps being integrally joined to said engagement portions adjacent said lower edges thereof and said straps having portions disposed laterally of the plane of said lower edges.

2. A ground bushing as set forth in claim 1 in which the free ends of said engagement portions are turned outwardly to bitingly engage the edges of an aperture formed in a support. 

